ACUTE NONCOMPRESSIVE NUCLEUS PULPOSUS EXTRUSION CAUSING PARAPLEGIA IN A SIBERIAN TIGER ( PANTHERA TIGRIS ALTAICA).

A neutered male Siberian tiger ( Panthera tigris altaica) presented with paraplegia of 5 days' duration. Thoracolumbar magnetic resonance imaging (MRI) revealed a focal, linear T2-W hyperintense intramedullary lesion at the level of T10-11 as well as reduced size of the nucleus pulposus of the T10-11 intervertebral disc. The animal was humanely euthanatized as a result of the severity of clinical signs and the poor prognosis. Gross necropsy revealed a dark red, firm focus on the spinal cord at the level of the T11 nerve roots. Histopathology revealed liquefactive necrosis of the ventral spinal cord at the level of T9-11, with hemorrhage and vascular changes within the cord and associated meninges. Fibrovascular tissue with hemorrhage, fibrin, and fragments of cartilage consistent with nucleus pulposus material was identified extradurally at this level. The findings were consistent with acute noncompressive nucleus pulposus extrusion.